Rooftop solar panel systems in the UK can produce enough electricity to power whole-home air conditioning for several hours during sunny spells, potentially offering a way to mitigate the costs associated with cooling homes during heatwaves. The synergy between solar energy generation and air conditioning demand is particularly strong because both peak during hotter, sunnier weather.
During a recent heatwave, a typical UK rooftop solar installation generated approximately 15kWh of electricity per day, according to estimates from the clean energy think tank Ember. This amount of energy is equivalent to the demand of a 3kW whole-home air conditioning system running for roughly five hours. Kilowatt-hours (kWh) measure energy consumption; for context, a 1,000-watt appliance running for one hour uses 1 kWh.
While the exact amount of electricity generated depends on factors such as sunshine duration, roof orientation, and shading, most UK homes with solar systems typically have installations ranging from 4kW to 5kW. These systems often comprise 10 to 12 solar panels, each around 400W.
The cost of installing a solar panel system varies, with professionally installed 4kW to 5kW systems generally costing several thousand pounds. Smaller systems or DIY kits can be less expensive. As temperatures rise and heatwaves become more frequent, the Climate Change Committee has projected that nearly a quarter of UK buildings might require active cooling in a warmer world. This increasing need for cooling is prompting homeowners to consider solar power as a factor in the financial calculation for air conditioning or heat pump installations.
At the current average UK electricity price of approximately 26.11p per kWh, generating 15.2kWh from solar could save about £4 compared to purchasing the same amount from the grid. Over a week-long hot spell with similar sunshine levels, these savings could accumulate to around £28. Therefore, solar panels can potentially provide enough electricity to run a 3kW air conditioning system for approximately five hours daily during peak summer sunshine.
However, the benefit is contingent on consistent sunshine. Households that use air conditioning while the sun is shining will see the most significant savings. Those who rely on cooling in the evening or at night might need to draw electricity from the grid unless they have a home battery system to store excess solar power.
Despite these limitations, the data highlights the complementary nature of solar panels and air conditioning. As summers grow hotter, generating electricity precisely when cooling demand is highest can help households reduce their energy bills during future heatwaves. Furthermore, households with solar panels can often export surplus electricity back to the grid, with some tariffs offering payments for units exported.
For homeowners considering solar installations, system costs for an average 4.5kW system can range from approximately £1.30 to £2.20 per watt installed, potentially reaching up to £9,900. Air conditioning costs can also vary, with multi-room systems in the UK typically ranging from £3,000 to £6,500 or more for a standard family home.